Like many have stated, only you know what works best for you. There really is no wrong vehicle. For me, the dependability and easy of maintenance on a step van sold me for one. But step vans have significant downsides. They are loud, handle like a fridge on a bobsled track, and not so sure I'd want to get into a major accident with it. But with the right Diesel engine/trans combo getting 25mpg+, driving with the door open, and ease of a build out like a box truck but without stepping up 3', step vans are pretty sweet. And don't forget about the aluminum body lasting, ummm, forever because they don't rust.
I lived in a Ford Expedition for awhile. That was all sleeping bag and Coleman cooler living. Was kinda cool, but not being able to sit up was terrible. Really only stayed inside to sleep. Then I got an old military maintenance truck to live in. Upgraded to a mattress with sheets and a small mini fridge. I felt like I was king of the road! But not being able to stand up was a real downer, plus the fridge was too small. Now I'm in the step van, and I can do jumping jacks inside and can put whatever size fridge in it that I want! Also keep in mind that all three of those vehicle were around the same price range, but as time went on, they got larger and oddly more fuel efficient.